Additive manufacturing processes, commonly referred to as three-dimensional (3D) printing, can be used to construct desired objects with possible applications in numerous industries (e.g., aerospace, automotive, medical, etc). Exemplary processes include, but are not limited to, electron beam melting (EBM), fused deposition modeling (FDM), ink jetting, laminated object manufacturing (LOM), selective laser sintering (SLS), and stereolithography (SL). Using such processes, a desired object can be modeled in a computer-aided design (CAD) package and printed using a selected build material. For deposition based methods, like FDM, the selected build material is typically extruded through a heated printer in a layered manner according to computer instruction. Printing in commercially available additive manufacturing devices, like, for example, the ARBURG™ Freeformer system, often occurs in a build chamber that can provide desired heating and temperature control based on the selected build material.
Many additive manufacturing techniques use support layers or structures to build a desired object. The limited availability of suitable support methods, materials, and structures, however, has restricted printing to certain design types. The most basic support method uses the same material for support as it does for the printed object, as, for example, shown in U.S. Pat. Nos. 6,228,923, 6,790,403 and 8,404,171. With this technique, the support is erected similarly to scaffolding on a building and “props up” any steeply angled overhangs or spans. Referred to as “breakable” or “raft” support, this type of support can be effective, but can also be messy, time-consuming, and difficult to remove by mechanical breakage or trimming. It is not unusual to spend hours cleaning or cutting away support material from a 3D-printed object using razor blades, scalpels, sandpaper, and even power tools. Methods using different support and printed materials can also be problematic. For example, certain hydrophobic polymers (e.g., polypropylene) are nearly impossible to print due to the incompatibility between the support materials and the 3D-printed base resin.
The inability to remove internal support materials can further restrict object design types. Some external geometries can make it difficult, if not impossible, to remove internal support material. For years, many have tried to solve this problem with support structures that are supposed to dissolve in very hot water, highly acidic or basic conditions, organic solvents, or various other chemicals. These products are often messy and even dangerous—and in general have been unsuccessful.